Final Environmental Impact Report - Whittier Bridge/I-95 ...

Whittier Bridge/I-95 Improvement Project FEIR
Chapter 1.0: Changes Since the Draft Environmental Impact Report and Resolution of Additional Issues
Table 1-4:
Riverfront Area Mitigation – Amesbury
Areas Subject
to RFA
Mitigation (sf)
Impact Estimates
Existing
(sf)
Impacted
Areas (sf)
Mitigation Rationale
Area of Riverfront on Site 64,000
Mitigation not required for redevelopment
Existing Degraded 16,460 N/A of Existing Degraded areas.
Previously Developed areas (i.e.
Engineered Side Slopes / Previously
Previously Developed
Graded Areas) may require mitigation
(Engineered Sideslopes) 6,000 6,000 under 310 CMR 10.58(5)(e)
Does not require mitigation under 310 CMR
10.58(4)(d)1, though undisturbed impacts
cannot cumulatively exceed 10% of RFA
Undisturbed 5,480 N/A on the lot.
Total 27,940 6,000 Permanent impacts
Does not require mitigation under 310 CMR
10.58(4)(d)1, though undisturbed impacts
Temporary Impacted Riverfront
cannot cumulatively exceed 10% of RFA
(Undisturbed) 0 N/A on the lot.
*Temporary Impacts will be mitigated
through "in kind" or in situ restoration, and
Temporary Impacted Riverfront
(Previously Developed) 11,650 *
therefore not included in the mitigation
calculation below.
Overall Total 39,590 6,000 Includes permanent and temporary impacts
Mitigation Calculations
10% of total RFA 6,400
Existing Degraded 16,460
Difference between 10% of site
and Existing Degraded = additional
allowed alteration without
mitigation -10,060
Area Of Permanent Previously
Developed Impacts 6,000
Required Mitigation under 310
CMR 10.58(e) 6,000
Proposed Restoration Area for
Permanent Impacts 11,800
Proposed Restoration Area for
Temporary Impacts 11,650
Total Mitigation 23,450
Note: Refer to Figure 1-8 for locations of impacted and restored areas.
Proposed Impacts to Undisturbed RFA
must not exceed 6,400 s.f. under 310 CMR
10.58(4)(d)1. (project is 920 s.f. below
threshold).
The proposed work may alter up to 10% if
the degraded area is less than 10% of the
riverfront area on the site; 310 CMR
10.58(5)(e).
The existing degraded area is over 10% of
the Riverfront Area on the site, therefore no
additional alteration is allowed unless
mitigated for; 310 CMR 10.58(5)(e).
Area requiring mitigation
Mitigation provided at an approximate 2:1
ratio for permanent impacts through
restoration of existing degraded areas.
Mitigation provided at 1:1 ratio for
temporary impacts.
Permanent Impact Mitigation + Temporary
Impact Mitigation.
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